Influence of Space Charge During the Oxidation of Metal Surfaces

• Published in: Oxidation of metals Vol. 90; no. 3-4; pp. 515 - 526
• Main Authors: Mukhambetov, D. G., De Los Santos Valladares, L., Kargin, J. B., Kozlovskiy, A. L.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-10-2018; Springer Nature B.V
• Subjects: Chemistry and Materials Science; Corrosion and Coatings; Film growth; Inorganic Chemistry; Materials Science; Metal ions; Metal surfaces; Metallic Materials; Metals; Original Paper; Oxidation; Oxide coatings; Simulation; Space charge; Surface charge; Tribology; Cabrera and Mott theory; Oxide film growth; Space charge influence; Metal surfaces; Surface oxidation
• ISSN: 0030-770X; 1573-4889
• DOI: 10.1007/s11085-018-9843-8

In this work we present a model for the surface oxide film growth considering the influence of space charge. The space charge field
E
sp
is assumed proportional to the charge of moving metal ions and electrons in the oxide layer. The surface charge field
E
ox
decreases as the Cabrera and Motts’ oxide thickness
X
grows to its limit
X
1
(
E
ox
 = 
V
M
/
X
).
E
ox
remains constant for further growth of the oxide film (
E
ox
 = 
V
M
/
X
1
). The obtained equation for the growing rate of the oxide film covers two stages. The first stage is characterized by a negligible space charge and is described by the typical inverse logarithmic law. During transition from thin to thick film, the oxidation growth rate is described by a direct logarithmic law which is confirmed by many experiments. At the end of this stage, the drift of metal ions is replaced by their diffusion that leads to parabolic law.